Kapteyn's Star was originally cataloged by the Dutch astronomer, Jacobus Kapteyn, in 1898.[10] While he was reviewing star charts and photographic plates he noted the star's very high proper motion of more than 8 arc seconds per year. Later, the star became referred to as Kapteyn's Star, in honor of its discoverer.[11] At that time, it had the highest proper motion of any star known, dethroning Groombridge 1830. With the discovery of Barnard's Star in 1916,[12] Kapteyn's Star dropped to second place, where it remains.[6][11] On 2014, two super-Earth planet candidates in orbit around the star were announced.[13]

Observation data
Epoch J2000      Equinox J2000
Constellation Pictor
Right ascension 05h 11m 40.58112s[1]
Declination −45° 01′ 06.2899″[1]
Apparent magnitude (V) 8.853[2]
Spectral type sdM1[2]
U−B color index +1.21[3]
B−V color index +1.57[3]
Variable type BY Dra[4]
Radial velocity (Rv) +245.2[5] km/s
Proper motion (μ) RA: +6,505.08[1] mas/yr
Dec.: -5,730.84[1] mas/yr
Parallax (π) 255.66 ± 0.91[1] mas
Distance 12.76 ± 0.05 ly
(3.91 ± 0.01 pc)
Mass 0.274[6] M
Radius 0.291 ± 0.025[7] R
Surface gravity (log g) 4.96[6] cgs
Temperature 3,570[6] K
Metallicity [Fe/H] –0.99 ± 0.04[8] dex
Rotational velocity(v sin i) 9.15[9] km/s
Age ~10[6] Gyr
Other designations
VZ Pictoris, GJ 191, HD 33793, CD-45°1841, CP(D)-44°612, SAO 217223, LHS 29, LTT 2200, LFT395, GCTP 1181, HIP 24186.[3]